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Modern Friedel–Crafts Chemistry. Part 37. Efficient Syntheses of Some New Julolidines via Cyclialkylations of Heteroaryl Carbinols
Author(s) -
Abd ElAal Hassan A. K.,
Khalaf Ali A,
ElKhawaga Ahmed M. A
Publication year - 2014
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.1797
Subject(s) - chemistry , friedel–crafts reaction , carbocation , intramolecular force , reagent , lewis acids and bases , aryl , organic chemistry , catalysis , acid catalysis , divergent synthesis , brønsted–lowry acid–base theory , alkyl , combinatorial chemistry
A simple and convenient procedure for the synthesis of some novel alkyl‐substituted and aryl‐substituted julolidines is reported. Julolidines were smoothly synthesized in excellent isolated yields via Friedel–Crafts intramolecular alkylations of heteroarylalkanols in the presence of both Brønsted (PPA) and Lewis (AlCl 3 /CH 3 NO 2 ) acid catalysts. The precursors alkanols, 1a , 1b , 1c , 1d , 1e , 1f , 1g , 1h , 1i , were readily prepared both by reaction of selectively synthesized carboxylic acid esters and ketones with different Grignard reagents and also by reduction of the synthesized ketones with LAH. A plausible carbocation mechanism is proposed to account for the results. The structures of the compounds are established using both spectral and analytical data.